Once again, this is another saga in my research and is a question pertaining to line arrays and mid/tweets involving my ever evolving project The project is an open baffle dipole and I will be crossing to Dayton RS390HFs on the bottom end.

I only have so much many, and have to decide which mids Im going to audition. I can get a pair of W15CYs for $220~, a pair of Audax PR170M0 for $160, and 8 Dayton RS180s for $200

Partsexpress is having a sale (RS180s are $25 each), this would allow me to use 4 RS180s per side or even 8 if I was feeling dangerous. This would allow me to achieve super low distortion and crazy efficiency:D ~100dB with 4 of them.

I'd arrange them in a MMTMM vertical alignment. Would I have issues with the outer mids being farther from the tweeter than the inner mids? The outer mids would be farther from the tweeter than the length of the soundwaves its reproducing by a significant margin. I'd be crossing 1800hz LR8 to avoid the breakup node, which is ~7.4".

Also, with non-linear distortion and linear distortion taking into consideration. Would 4 of these RS180s outperform a Seas Excel W18E or W15CY?

thylantyr

12-19-2006, 03:10 PM

An MMTMM isn't really a line array. A real line array in a home would be an array
where the driver line is close to the floor and up close to the ceiling. Anything
else is a compromise, which is ok. Alot of people are making compromised
line arrays because their budget doesn't support the big line array or other
reasons why they can't have a tall tower in the home. I prefer to call these
hybrid arrays as their performance will be different than a real line array, but it
doesn't make the design bad, just different.

I had plans to make a hybrid array, two tower array using four pro planars,
four 8" midranges flanked by three 15' wideband woofers, but after
experimenting with the budget array using 49 cent modded 4" midwoofers
{PE buyout drivers}, and PT2 planars, I realized that the big array even using
cheap drivers, optimized design, has huge performance capabilities and I only
imagined what a real line array could do if you were to use high end drivers. Since
then I changed my mind completely and will only make full line arrays, no hybrids
even if using quality drivers.

You will find many arrays where they use alot of midranges and only one tweeter.
You will find short line arrays where they use 4-6 midwoofers and a small line of
{small center-center spacing} dome tweeter or planar/ribbons. I haven't found
any DIY or commercial line array except my budget array that is wired for low
impedance to gain maximum performance. These folks who have high end line
arrays have not seen the full power of what they can do. lol ..... yet they are completely amazed by them.

The hybrid array in your case would be a minimum requirement of MMMMTMMMM
design. The general rule is that the distortion would be 1/8 of the single driver
distortion at the same SPL level - because you have 8 drivers. My budget array is
16 4" midwoofers and distortion is 1/16 of the single driver. As you see, more
drivers, less distortion = sweet. More drivers also means line array midrange
sensitivity rises. Wire them up for lower impedance, you get another higher
sensitivity boost. This hybrid array has a tweeter bottleneck. The overal
performance of the line array is limited to the performance of the single tweeter.
Because you have to match the tweeter to that big midrange line, you will reduce
gain on the midrange line so it's not overpowering the poor ole' tweeter so
you will never really realize it's full potential, all you get is very low midrange distortion. A better design would be to make the tweeter line equally as uber
as the midrange line so you can push performance to it's limit. It would be like
building a muscle car with an uber 500 horsepower engine, but you are using
a weak transmission and skinny tires. The engine looks impressive when you
show it off, but the car isn't going to perform to it's full abilities.

I'd arrange them in a MMTMM vertical alignment. Would I have issues with the outer mids being farther from the tweeter than the inner mids?
It's a compromised design so you have to accept the gremlins that may manifest
because the top array segment is spaced further apart from the bottom segment.
In the real world, you have no choice unless you move the tweeter to the right
of the baffle and make the midrange line with no break. The speaker will look
fugly and this is where art takes priority over sound theory. I'd choose the compromise and just live with it.

Also, with non-linear distortion and linear distortion taking into consideration. Would 4 of these RS180s outperform a Seas Excel W18E or W15CY?

When you line source drivers, distortion drops alot and it's easy to beat
out single drivers. My 49 cent midwoofers, all 16 of them would beat a single
Seas Excel when you crank it up loud, no contest. The power of the large
quality of drivers just rule.

If you want to make a line array, select the tweeter first as you are limited by
choice. Make a full line of tweeters, then choose 4" - 5" cheap midwoofers
and performance will be huge. SQ will be defined by the tweeters and less by
the midranges.

Here's a Dayton RS/PT2 array that someone started to build last year
based on my recommendations.

pics in numerical order.
http://home.pacbell.net/lordpk/ew/

If you want to order sample drivers to audition, then just buy one driver
and return the ones you don't like. If you want to make a big line array,
you really don't need to sample any midrange drivers -- because -- you will
not be pushing the midrange to it's performance limit in an array as much
as you will in a standalone design. Gremlins manifest when you push the driver
hard and you want to identify which ones take the abuse while sounding clean.
For an array, it's hard to push each driver to it's limit unless you have some monster kilowatt proamps in bridge mode, even so, distortion of the array is
uber low so the midrange candidates can realistically be any cheap driver
especially if you use a LR8 crossover under 2khz crossover point.

If it was me, I'd either make a quality 3 way speaker using one tweeter, one
midrange, one woofer, subwoofer seperate.... OR I'd chose to make a tall line
array using PT2 planars with cheap midwoofers. If you have bigger bucks,
use $100 ribbon tweeters and Dayton RS or higher brand. If you want to use
domes, there is little choice on the market, the Dayton Neo $4 dome is the
one typically chosen, but you need alot of them for a big line.

thadman

12-19-2006, 05:25 PM

Do you think 8 RS180s per side and 32 Dayton Neo4s per side would sound good? The Neo measured absolutely horrendously (1% distortion <2500hz 2nd harmonic, and the 3rd harmonic is only a few dB down), could it sound good with 32 per side?

I'd have crazy efficiency:D

102.65dB with 1 watt to each RS180

122dB with 1 watt to each Dayton Neo

I also have the possibility of building an ESL (60" high by 1" wide). Could it keep up with the RS180s if crossed at 1800hz?

Itd only cost me $400 for the RS180s and ~$250 for the Neos (although I bet id get a discount by buying 64 of em hehe) so cost wouldnt be bad at all.

thadman

12-19-2006, 07:08 PM

Also, how long of a line determines its potentiality as a line array. Im sure its frequency dependent, but how long does the line have to be in comparison with the frequency its reproducing?

baseballer1100

12-19-2006, 07:09 PM

thast a lot of typing.

thylantyr

12-19-2006, 08:02 PM

Do you think 8 RS180s per side and 32 Dayton Neo4s per side would sound good?

http://www.partsexpress.com/pe/pshowdetl.cfm?&Partnumber=275-035

I think you can make it sound good as you have a DCX to fine tune the the sound.
The midrange and tweeter line is pretty good in size. $256 for 64 tweeters.
Call to see if you can get a volume discount. For $400 you can get 16 PT2 planars which would make the install much easier, woodworking and wiring point of view.
[10 - 12 PT2 per tower = better]

The Neo measured absolutely horrendously

The PT2 is also pretty bad if you test it, but in an array, distortion drops alot
compared to the single driver at same SPL. In the real world, it's a moot issue
as you will have low distortion. Only at very high SPL will the issues manifest.
These are SPL levels that high end drivers can't reach. 32 Neo's has the potential
of 1/32 less distortion of the single Neo at same SPL. My budget array has 10
PT2's, 1/10 the distortion. Add the fact that an LR8 crossover is sweeter and will
allow you to push the performance envelope further on either tweeter, Neo or
PT2. I cross the PT2 at 1.7khz whereas everyone else doesn't go below 3khz
using a simpler crossover.

I'd have crazy efficiency:D
102.65dB with 1 watt to each RS180
122dB with 1 watt to each Dayton Neo

I also have the possibility of building an ESL (60" high by 1" wide). Could it keep up with the RS180s if crossed at 1800hz?

You can make it work, you adjust our RS line gain to the level of the ESL line. I'm
pretty sure the ESL is your bottleneck SPL-wise unless you have something
unique that puts out gobs of SPL.

You want dipole but check out a sealed or ported design for the line array.
RS180 line array can dish out incredible midbass if you feed it kilowatts. A ported
RS line tuned to ~45hz can do more punishment. You shouldn't need those 15"
woofers to play the role of midbass if you make a big line array. You can save
money by not needing the woofers and amplifier, redirect all the funds into the
biggest array that fits in the house. You can push the array taller to squeeze
more drivers in there for a no compromised design. If dipole, you might have
some lack of midbass, you'd have to test it out to see.

If you want to refine the line array design for best SQ, a line of 12 RS150's or a
line of 16 RS125's 5" midwoofers would be pretty sweet. The 4" - 5" midwoofer
is probably the best size for a line array but you can make a line array work
very well with the 6", 7", or even 8" midranges. I have plans to use 8" pure
midranges for a future build even though 8" is not SQ - ideal... I'm looking for
more SPL and dynamic impact, an unusual goal, but for the common man,
the 4" - 5" driver would be best.

Word on the street says the RS180 has SQ gremlins at a higher crossover
frequency, IIRC a crossover ~1.7khz, 8th order is needed to filter out the crud,
but this leaves you with little tweaking ability. The RS150 actually would make a
better candidate as if offers more crossover frequency flexibility. Best SQ might
be achieved by using the RS125 but you need more of them to keep the line
array tall.

The John J. line array is one of the biggest DIY arrays with 12 PT2 'type' planars
and 12 6" midwoofers. By have extra drivers, you boost performance.
http://home.pacbell.net/lordpk/temp/5.JPG

If you make a good line array, you won't need any other loudspeaker ... ever ...
Take time and be patient, think about it.

thylantyr

12-19-2006, 08:03 PM

thast a lot of typing.

I'm new to ca.com

I've noticed that many people complain when posts are long.

Are people here handicapped at reading ?

:laugh:

thadman

12-19-2006, 08:53 PM

How long does the tweeter array have to be for it to display line array behavior? Are there varying degrees of line array behavior (SPL loss for a given distance) that rises with frequency like directivity in comparison with diaphragm size or is it simply black and white? or no...

Can I just have a line of tweeters that will cover the distance I will be listening (say 36"-60") vs the entire line? Because isnt the requirement for the length of the line lower for higher frequencies?

ssj2xxgotenxx

12-19-2006, 08:59 PM

I'm new to ca.com

I've noticed that many people complain when posts are long.

Are people here handicapped at reading ?

:laugh:

It's not that... just get to the point. Try compressing what you want to say.

thadman

12-19-2006, 08:59 PM

I could optimize the ESL design by making the stators extremely close together, this makes sensitivity go through the roof because it has to do with a square of the distance, but severely reduces displacement (I wont need it anyway though if Im reproducing 1000-1500hz and have an extremely large diaphragm)

Does this sound like an option...or is this still a bad idea?

thadman

12-19-2006, 09:03 PM

Im a fan of thylantyr's extended posts and find no issues with them. They are extremely informative, detailed, and coherent. The subject matter in many of the threads are already quite complex, so a complex and relevant post is often welcome:D

thylantyr

12-20-2006, 12:07 AM

How long does the tweeter array have to be for it to display line array behavior? Are there varying degrees of line array behavior (SPL loss for a given distance) that rises with frequency like directivity in comparison with diaphragm size or is it simply black and white? or no...

Can I just have a line of tweeters that will cover the distance I will be listening (say 36"-60") vs the entire line? Because isnt the requirement for the length of the line lower for higher frequencies?

Have you read this doc yet?
http://www.audiodiycentral.com/resource/pdf/nflawp.pdf

A small tweeter line will not be as uber as the big tweeter line. If you can't
afford to make the big line array, I probably wouldn't bother with the hybrid
design because later you will have second thoughts and wonder ...hmmm maybe I shoulda made the big one .. lol

Most people that build the big array will have a listening distance at least 12
feet from the array and even beyond this, it's pretty crazy SPL wise. You have
to experience the big array to realize the small one just isn't the same.

If I were to make a hybrid array, I would use a quality compression driver with
small horn in the center of the array flanked by the midwoofers. This gives
the horn a chance to compete with the SPL potential of the midwoofers. People
have successfully made a hybrid array with a center ribbon or dome tweeter but
you just need to know that it's the bottleneck of the design.

The SQ of my budget array is defined by the long line of PT2 tweeters, the midranges really don't play a big role. People that build arrays don't realize they
are losing SQ when they compromise the tweeter line design. My budget array
has one fuse per tweeter. I can disconnect each tweeter from the line to see
how it sounds with just a single tweeter or two, it's just not as uber in SQ
and performance.

thylantyr

12-20-2006, 12:14 AM

I could optimize the ESL design by making the stators extremely close together, this makes sensitivity go through the roof because it has to do with a square of the distance, but severely reduces displacement (I wont need it anyway though if Im reproducing 1000-1500hz and have an extremely large diaphragm)

Does this sound like an option...or is this still a bad idea?

Make a prototype, then see if it fits in your speaker design.

thylantyr

12-20-2006, 03:19 AM

With the DCX using LR8 @ ~2khz crossover point, you can make almost any
midrange work, the ones with Fs around 100hz or less is what I would look at.
If you build the tallest array by cramming alot of midranges, then you don't
really need the midrange to be a high end driver as distortion will be low
using el cheapo driver.

Buy two Fosters for $6. Since it's a paper cone, do an experiment with
lacquer cone treatment. Cost ~ $5 to cone treat. Listen to the unmodded vs.
modded driver to see which has smoother sounding midrange playing full range.
Then hook up the DCX bandpass and listen.

How do I overcome this problem? Im going to be listening in the far field at lower frequencies...and the near field at the higher frequencies and theres no way I can overcome the height issue, my room is only so high lol.

Also for nearfield listening F/2 is the CTC spacing requirement (ctc spacing of RS180s would be 7.125" and would require a 14.25"(940hz) crossover)

That line array document by Jim Griffin also says that if you place your array in
a room, you will get under 100hz performance provided that your midwoofers
are up to the task.

Some key things to remember. Science is good. But you can use your common
sense card in your back pocket and figure things out and you can also skew any
design and cheat a little bit. That is the fun of DIY - to make your creation with
a touch of art.

Do you really think 24 7" Dayton RS midwoofers in a sealed box won't give you
low frequency performance? Of course it will. Not only that, power handling is
huge, 720w rms per line array. You can drive that line with a 10kw proamp
and wake up the dead with so much bass.

Take another look at my NSB/PT2 array I built for my friend a while back.
http://home.pacbell.net/lordpk/robarray/1.JPG
He hasn't taken possession due to lack of funds so it's mine at the moment and
I have alot of hours logged messing with it. Those NSB drivers are 4" Pioneer
buyouts from partsexpress that cost 49 cents each. 5w rms, xmax 1 mm.
It's a ported design tuned to 100hz. Wired for 2 ohms per midwoofer tower.
One PLX3402 in bridged mode drives that 16 midwoofer line. I measured over
126dB[c] at the listening position of just upper midbass. I have stuff falling off
the TV if I crank up the tunes. Recently a fancy wine glass fell off the shelf in
the kitchen. If I stand in the corner of the room, I can feel the bass pounding
in my chest. This is spectacular performance from 49 cent drivers in a ported box.
Performance is not as aggressive in a sealed box. Midbass performance would
complete lack if it was open baffle.

Imagine what you can do with quality drivers like Dayton RS in a sealed box
or imagine how crazy it can be in a ported box tuned low. In the DIY world,
I haven't seen any ported midwoofer line arrays except mine. There is one
commerical product - Dali-Megaline - that ports 1/2 of their midwoofer line.
Even Wilson Audio normal loudspeaker, Alexandria [$100k] has ported midwoofers in spite that they use two more woofers. It's not common to see
ported midwoofers as people frown upon that, but you can easily make a test
box to see what you like. Buy some cheap particle board and make a ported test box, reduce scale of your line array, lets say 1/4 scale. Listen to it ported. Plug the port then listen to it's sealed box performance, then take the box apart {destroy it] and run open baffle. One test box can test all three configurations to see what
you like.

The crossover frequency can be cheated and crossed higher. I think the
Dayton RS 6" or 5" would be better suited for the line array job. You can
take the crossover up to 2khz no problem. I bought 8" midranges for a future
line array build, I will probably use 1.8khz crossover point as I will cheat.

If you use the DCX, the job is much easier to execute.

Line array tweeter choices are limited.

If you want to use planars, PT2 is the best bang for buck wired for low impedance. <$25 in bulk purchase each.
HiVi planars costing more won't give you anymore reward, it's the same thing really in a different guise.
BG Neo8 is overrated, $62 each. There are some DIY and commercial line arrays using them. Of all BG drivers,
the Neo3 looks better but it's still expensive. Partsexpress $4 neo is probably the only dome out there suited for
this job. Then, you venture in the $100 ribbon territory, then $300 ribbon, then $700 planar.

There are some esoteric ideas floating in cyber where you use a RD ribbon like this;
http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=264-700
then mate this to a super tweeter line as the RD performs more like a midrange not tweeter.

Newform ribbons look nice, expensive too but all these long line ribbons or planars will lack
in SPL and have low sensitivity. If you use the smaller ribbon/planar it gives you the wiring
option for low impedance to raise sensitivity and you can get more SPL.

thadman

12-22-2006, 05:20 PM

I am going with an open baffle design to remove bass nulls...and its an all around easier design to build (wood is cheaper too). I doubt that even if I did run them open baffle, I'd have problems running them low...I never mentioned that.

The issue at hand is not that it lacks displacement...which it certainly doesnt. It is that the line is going to transition polar response in the midrange and make it impossible for me to listen at different distances. Below the transition frequency, the sound will be dominated by reflections and decrease at a rate of -6dB for every doubling of distance vs above the area the sound will be dominated by the cylindrical wavefront and decrease at a rate of -3dB for every doubling of distance. This cannot be fixed with equalization...

I dont understand your point about cheating...if I cheat I get comb filtering and/or poor performance. Its black and white...nothing subjective. I cant *bend* science...lol.

Why should I worry myself about wiring for low impendances? It seems pointless and I'd risk ruining my amplifier. As long as I deliver the power necessary to the line array...then Its going to reach the same SPL no matter the wiring configuration.

thylantyr

12-22-2006, 06:25 PM

Line arrays are not for everyone. I think their strong points are;

1. Potential for a big sound stage.
--> you can implement power tapering to reduce the image size but max SPL
is less and distortion can be higher than a non power taper setup.
2. Potential for very low distortion.
3. Potential for very high SPL.
4. Potential to be expensive as you need many drivers.
5. Potential to be heavy and take up alot of space in the room.

You should only seek a line array design if a standard design is boring. If
you find satisfaction with a standard design then it might be a better choice.

Model performance in an open baffle design, ideally prototype it first using
a hunk of cheap wood. Verify.

If the line array is for a typical room in a house, lets say 5-20 feet listening
distance, then there is little to be worried about other than having the normal
room treatments on the walls and carpet/rug on the floor. Maybe add some heavy drapes behind you.

You are analyzing way too much. This is simple stuff. A stack of drivers near
the floor up to the ceiling, following the common rules and even cheating the rules, plus a fully active setup with DCX,
anyone can make it work great.

The hard part is opening up your wallet and taking money out. The next hard part is choosing midwoofers and tweeters,
selecting OB, sealed or ported enclosures, then you figure out how much SPL you want by wiring the
array for higher SPL {lower impedance} or normal SPL {normal impedance},
choosing amplification, and fine tuning with your DCX. The fact that you will use
a fully active rig with DCX gives you so much flexibility to make this work well,
unlike a passive crossover design where you will use one amplifier to drive the array. There is more obstacles in your path using that method.

I dont understand your point about cheating...if I cheat I get comb filtering and/or poor performance. Its black and white...nothing subjective. I cant *bend* science...lol.

The line array math gives you a guideline to follow, it's not written in stone
as it must be that way. If your crossover is theoretically suppose to be 1khz,
setting it to 2khz doesn't guarantee bad sound. In fact, you might think it sounds better as you balance the lesser of the evils.
That's why you have an adjustable crossover, you sweep the vast frequency range to understand the audible effects. For instance, if I turn off
my tweeter array and just listen to my midwoofer array and sweep a crossover
frequency of 1khz all the way up to fullrange, it's not like the sound is horrible.
Most people would probably like the sound full range over 1khz because they
don't know any better. I can tolerate a high crossover from the midwoofer line
no problem. The real issue is the tweeter line.

tweeter line
Your tweeter line will define the SQ. You will perceive better SQ if you concentrate
the bulk of your money into getting a good tweeter line built and use cheaper
midwoofers.

The way I adjust my array is;
1. I turn off the midwoofer line.

2. I turn on the tweeter line. I sweep the crossover frequency from a low
starting point and sweep up while listening to my favorite music. Do this at
medium SPL so you don't damage your tweeters if you have a low crossover point. You will hear things as you sweep and
eventually you will favor a certain crossover point that sounds sweet. For sake of argument, lets say you like
the sound of your tweeter line at 1.2khz LR8 at low SPL, but at medium SPL the tweeters sound nasty and
you need to raise this closer to 1.7khz. For high SPL you may need 2.5khz. I make a mental note of these
three crossover frequencies; 1.2khz - low spl, 1.7khz medium to high spl - 2.5khz very high spl ..

3. Next, listen to the midwoofer line only and determine how your midwoofer
line sounds in the 1.2khz - 2.5khz range. If nothing bad is heard, then you
are good to go.

4. Listen to the midwoofer and tweeter line from 1.2khz - 2.5khz and you will see
imaging improve at the lower crossover point, but if it's too low and SPL is raised,
the sound degrades. For me, I do 90% of my listening at 1.7khz LR8, at extreme
SPL I will take it to 2khz, maybe 2.5khz to protect the tweeters and lower tweeter distortion.
For very low leveling listening , 1.2khz works fine, but so does 1.7khz and
2.5khz.

DCX has the ability to store settings. A huge bonus. Make different settings and
store them in memory. Recall your settings from memory on the fly.

Basically, I cheat. I cheat the theoretical crossover point because gremlins
that may manifest aren't audible, therefore no need to worry about it. I cheat
by choosing different crossover frequencies for my listening mood, SPL level I listen at and even the song
I listen to may sound better with a different setting to compensate for recording issues. DCX = ultimate cheater processor for $250.

[b]Why should I worry myself about wiring for low impendances? It seems pointless and I'd risk ruining my amplifier. As long as I deliver the power necessary to the line array...then Its going to reach the same SPL no matter the wiring configuration.

Low impedance wiring can raise sensitivity. You get higher SPL for the given
watt until you reach the drivers limits. I have four PLX3402's in bridge mode
wired like so;

If I flick a switch on the back panel.
http://home.pacbell.net/lordpk/robarray/Control_Panel-2.JPG

I can select a higher impedance to make it more amplifier friendly.
0.8 ohm tweeters are now 3.2 ohm. 2 ohm midwoofers are now 8 ohm.
I lose 6dB sensitivity in higher impedance mode and even though I drive
the array with four 3400w amplifiers, I do notice the lack of SPL. The reason
I notice the lack of SPL is because the amplifiers have reached their clipping
headroom first before the line array hit it's performance peak. Unless
you have an amplifier with unlimted headroom and power, then you don't
need low impedance wiring. Low impedance wiring is a neat trick to boost
performance and nobody, not even commercial line arrays use this method because the audio industry doesn't do fully active systems with 10kw of headroom. lol ...I'm just telling you the best kept secret in line array design.. shhhhhhhh...

If your amplifiers can't handling low impedance, then you have no choice
and can't wire it up this way. My design has a switch to select low and high
impedance to make the line array user friendly. I had a four channel
chipamp running this array in high impedance mode. LM4780 based system.
It works fine, you get sound, it's going to satisfy everyone, but it's not going
to push the line array to it's peak performance like the proamps do.

If you plan your line array wisely, you can make a killer system if you
think ahead. Implement an impedance switch so you can use low powered amplifiers, later if you want to exploit more potential, get some monster amps,
flick the switch and you are good to go.

Good amplifiers can drive low impedance tweeters with ease because tweeters
won't be a difficult load. PLX is rated for 4 ohms in bridge mode, no less. It runs
the 0.8 ohm tweeter load. My Adcom 555 was driving 0.8 ohm per channel,
it's not rated for less than 4 ohms per channel. At very high SPL for a while
cranking metal music, it did go into thermal mode as there is no fans to cool off
the heatsinks. I run the midranges at 2 ohms, I think the amplifiers might have
some issues at under 2 ohms in bridged mode. Woofers; use manufacturer
recommendation and don't cheat by driving lower than recommended. Chipamp
systems; they are not robust enough in design to allow impedance cheating.

joetama

12-24-2006, 12:02 PM

Mother bird is at it again.... I leave for a couple of days and all this line array crap comes right back up..... :(

thadman

12-24-2006, 01:37 PM

Not a fan of line arrays? Care to share your opinions:D ?

thylantyr

12-24-2006, 03:43 PM

Mother bird is at it again.... I leave for a couple of days and all this line array crap comes right back up..... :(

Can we help make your vacation longer? I will pitch in a few dollars :laugh: :laugh: :laugh:

You Know You Like

line array speakers [tm]

thadman

12-25-2006, 02:05 AM

I'd really like all the opinions I can get on line arrays...so my learned understanding of them isnt from one biased source.

So please, I'd love to hear your opinion of them:D

joetama

12-25-2006, 02:30 AM

Well.... My opinion is simple......

If **** smells bad outside of a bag, putting lots of it together in a big bag doesn't make it smell any better.

Basically, for me an effective line array design would not be practical because I would have to have higher end drivers in it. Which means LOTS of money. The benefits to me aren't worth it. Because, really, if you want volume 12" and a horn is the way to go. If you want clarity, a conventional speaker system is the way to go. If you want both, check out Meyer UPA or UPJ Ultra Series Power stuff....

Unless you really want to blow some cash then the Dali Megaline stuff would be great.

The "Line Array" as people call it really isn't a line array anyway, it's a line source aka column speaker. I know I know, thy is going to jump up and down on his key board and post 20 articles that say it isn't. But to me it is and most people who were schooled in the pro-audio world would agree, they use pretty much the same idea, small drivers to develop a coupled sound to create a tight patterned control so that a series small drivers can sound like big ones. If you are having issues with your current system not getting loud enough the well maybe you should look into a horn loaded top end with a large mid end which will extend to match the horn.

But, I personally don't see the benefit of using a Line Array in a home setting....

thylantyr

12-25-2006, 04:17 AM

I'd really like all the opinions I can get on line arrays...so my learned understanding of them isnt from one biased source.

So please, I'd love to hear your opinion of them:D

I started following the DIY home audio line array camp many years ago when
Jim G. make the Linus I array and documentation for that array. This project
probably started the big DIY line array movement and ever since it has gained
popularity. Everyday I scan all the forums looking for data. I've noticed alot
of people building what I call the hybrid arrays, not the full blown line arrays.
Even so, those have positive reviews. In a way, the hybrid array is giving a
false impression on what a true array can do as people that don't make the
real thing are missing the boat.

A few years ago I started to collect testimonials from around the internet as
people started to audition the good DIY line arrays. I found some commercial
line array testimonials also. I wanted to get an idea on how people responded
to those designs vs. conventional design. I compiled a list here dated September
2004.

Rick Craig with or without Jim's aid, developed many line array designs, I have
alot of line array pics offline that I collected over the years.
http://www.selahaudio.com/

The bottom line was. There are too many positive testimonials from DIY
and some commercial line arrays that validate the concept of using them in
a home. Due to human nature, you can't satisfy 100% of the crowd, but
the positive bias towards line array drowned the negative.

There are some commercial designs not well executed, but you will find
some that are well done but very expensive.

Unless you build a true line array and maximize it's performance 100%,
there is no way someone can really understand how they work, they need
to experience them.

thylantyr

12-25-2006, 05:01 AM

Well.... My opinion is simple......

If **** smells bad outside of a bag, putting lots of it together in a big bag doesn't make it smell any better.

Before I built the budget array, I did some preliminary tests using eight RT2
planars on the test bench. Back then, these drivers were hyped up on Madisound
forum as they were discounted alot. I did some preliminary tests. For $25, those
RT2 were ok in sound standalone. I much preferred to invest more money into a
quality dome tweeter. But eight planars wired for 1 ohm revealed a different
performance behavior that was interesting and it can't be ignored. How can an
ok driver make the sound better just because you use more of them and if
you wired them for low impedance, how does performance rise? The answer is
simple as I already posted why in this thread.

Later, another test;

Ten planars, 65" line = $250
One pro planar, 8" line = $700

I compared the array of cheap planars to my single $700 planar. The pro planar
can generate as much SPL as the array of cheap planars in a typical room,
offer a lower profile design, 8" vs. 65", but the sound stage is normal, not big
like the line array can do.

Basically, for me an effective line array design would not be practical because I would have to have higher end drivers in it. Which means LOTS of money. The benefits to me aren't worth it.

The good commercial line arrays cost $40k on up. For $3k in driver cost, I can beat the $40k array DIY-style.
$3k is alot of money, but what two speakers will you find in the store that cost $3k for a pair that will beat
the DIY project ?
Answer: none.

For ~$1500 in driver cost you can make a sweet line array that can beat
$20k loudspeakers found in the store.

Based on my experiments, you don't need high end drivers to make
a great line array. A person should not be dissuaded because they think they
need expensive drivers. My budget array cost $2k total less labor costs. I
compared the performance of it to the local high end store where their best
room was McIntosh electronics with B&W speakers [$16k for a pair.]
My budget array using DCX with PLX proamps kills that system with ease
for a fraction of the cost :laugh: ** That's why people DIY their speakers,
to get the huge rewards while saving phat dollars.

Because, really, if you want volume 12" and a horn is the way to go.

For home use, horns can generate alot of SPL and SQ can be compromised,
the majority of the time it is. I have used horns for 20 years and even though
I'm an SQL junky, I won't use horns in my house. I want high SQ with horn SPL,
the line array is perfect to accomplish this goal. If you don't need this, then
a line array is overkill.

If you want to make a classic pro audio system for a home using a horn, 10" midrange, 15" midbass, etc., then use this recipe.
http://www.audioheritage.org/html/perspectives/drews-clues/system.htm

It will sound good and unique in it's own way, but an entry-level Dayton array will be
superior if you go active with it and give it some power just like that system does.

If you want clarity, a conventional speaker system is the way to go.
Line array can do this too.

If you want both, check out Meyer UPA or UPJ Ultra Series Power stuff....
DIY for-the-win, not commercial products. :naughty: Price????

Unless you really want to blow some cash then the Dali Megaline stuff would be great.

Dali is one of the better affordable line arrays on the market. IIRC, $40k
for a pair. In the home audio world, a $20k array is cheap, bad design. $40k
gets you a proper design, then it can get crazy and you will see >$100k, $200k
systems. There is one system that retails for $600k. I can beat the Megaline for $3k in driver cost
not counting building materials, electronics and labor costs. When it comes to DIY line array,
the savings is huge vs. store bought not to mention you can kill those store bought systems
with minimal effort in design.

The "Line Array" as people call it really isn't a line array anyway, it's a line source aka column speaker.

Why even bring this up? :laugh:

But, I personally don't see the benefit of using a Line Array in a home setting....

There are many benefits, resistance is futile :laugh:
http://www.familyrightsassociation.com/educate/borg/talons.gif

Last words. After reading those line array testimonials and doing my own experiments
plus building the budget array, the comments correlate to my findings. The line array
is a valid design for home use but there is no guarantee that it will satisfy everyone.

joetama

12-25-2006, 10:50 AM

Well this is where we just totally disagree. I DO NOT like Column speakers in my listening enviorment. And you love them. The thing I hate is how everyone jumps on that band wagon with out knowing. Which is the problem with DIYers is most of them don't know what they are doing but think they know more than everyone else.

joetama

12-25-2006, 11:11 AM

Seriously man.... I just came back for another read at this when I'm not straight out of bed. And I am pretty sure you are the most obnoxious person I have ever met. UNless you are some sort of audio super genius, I seriously doubt that your stuff sounds better than the B&W/Mac rig. Maybe louder, but I have NEVER heard a column speaker that I liked. Also, I understand the whole "Loook what I can do" mentality of DIY, but if DIY was so awesome wouldn't everyone just build their own stuff????? You always talk about the "placebo" effect well don't you think you are undergoing a little mind bending when you say statements like that?

It just makes me sick.... Now people on here will be screaming "Line Array Line Array Line Array" for months now. BOLLOCKS!!

thylantyr

12-25-2006, 01:27 PM

Well this is where we just totally disagree. I DO NOT like Column speakers in my listening enviorment. And you love them.

Feel free to hate whatever you want, freedom of speech rules. There is
no real reason to bash people that are interested. DIY loudspeaker; it
has a history of providing satisfaction. Your hate for DIY will not stop people, lol.

Which is the problem with DIYers is most of them don't know what they are doing but think they know more than everyone else.

From my observation in cyber. You have a mix of people who know what they
are doing, many DIY'ers build proven designs, and some don't know what they
are doing but make the DIY attempt to learn. The process of learning is called
process as they mature in knowledge. This is not limited just to audio.

And I am pretty sure you are the most obnoxious person I have ever met.
For the record, we never met. :laugh: Reading posts on forums doesn't really
qualify to know someone.

UNless you are some sort of audio super genius, I seriously doubt that your stuff sounds better than the B&W/Mac rig.
If store bought speakers satisfied, then I wouldn't have a DIY loudspeaker hobby,
I'd be listening to my store bought rig ever since I got into audio.

but I have NEVER heard a column speaker that I liked.
Considering that line array speakers for proaudio wouldn't work well in a home
except one system I saw from a new vendor, plus considering that there aren't
many store bought line arrays that are great, and not many available for audition,
it would be interesting to see which line arrays didn't satisfy you. I wonder if
the design is flawed? We already identified a few commercial line arrays that
are flawed in design.

Also, I understand the whole "Loook what I can do" mentality of DIY, but if DIY was so awesome wouldn't everyone just build their own stuff?????

People have diverse reasons to DIY.

DIY is popular.
* How many people in the world DIY and not participate on forums? Alot.

* http://www.diyaudio.com/
[as of today -> 1,096,985 posts

* http://www.madisound.com/cgi-bin/audio_forum/index.pl

* http://www.pesupport.com/cgi-bin/config.pl?#175391

* http://www.avsforum.com/avs-vb/forumdisplay.php?f=155

* http://www.htguide.com/forum/forumdisplay.php4?f=6

* http://www.audioroundtable.com/

* http://www.audioasylum.com/index.html

Plus many more forums of people building their own stuff.

joetama

12-25-2006, 02:31 PM

Yea.... Well I normally don't comment on this Column speaker stuff, because we just don't see eye to eye on it. Which is fine, I don't like you I'm sure as much as you don't like me. But, the dude wanted my opinion so I gave it. And BTW, I realize I don't know you, and that probably is a good think that I don't. If you would stop being **** about stuff you would realize I meant, I know you on the internet. I don't know you in real life, you might be a fantastic person and really know what you are doing. BUT, I totally and whole heartedly disagree with you on this line array stuff and so it creates a problem.

So, whatever.... Do what you want and what makes you happy. I do!!!!!!!!!!

Just don't brain wash people with 1000000x articles that you found that agree with you. I can find plenty that agree with me. I just don't blow my time being on the internet that much....

thylantyr

12-25-2006, 03:35 PM

Yea.... Well I normally don't comment on this Column speaker stuff, because we just don't see eye to eye on it. Which is fine, I don't like you I'm sure as much as you don't like me. But, the dude wanted my opinion so I gave it.

I don't have bias towards or against you. I'm just into DIY audio and encourage
people to try things.

repost;
************************************************** ***********
but I have NEVER heard a column speaker that I liked.
Considering that line array speakers for proaudio wouldn't work well in a home
except one system I saw from a new vendor, plus considering that there aren't
many store bought line arrays that are great, and not many available for audition,
it would be interesting to see which line arrays didn't satisfy you. I wonder if
the design is flawed? We already identified a few commercial line arrays that
are flawed in design.
************************************************** ************

.. waiting to find out which line arrays didn't satisfy you...

Just don't brain wash people with 1000000x articles that you found that agree with you.

Audio is subjective, the idea is to collect data to find out if an idea is valid.
What articles? lol ...

I can find plenty that agree with me.

Post data that supports your case, just like I posted data that supports
my case.

I just don't blow my time being on the internet that much....

:laugh:

I've had disagreements with others on line arrays, you are not the first one.
But those other folks gave a valid response why they didn't like the sound.
I still haven't heard the reason why you hate line arrays. The only opinion
you gave was just random hate babble. Express your feelings why the sound
was weak? Which systems did you hear?

thadman

12-25-2006, 05:06 PM

I'd love to understand *specifically* why you dont like line arrays.

Soundstage too big?

Not enough reflected energy?

Im trying to get the most objective perspective, and im glad im getting another opinion on these speakers.

joetama

12-25-2006, 06:15 PM

Well first of all I have heard DIY ones before. But they were configured for the most volume they could get out of them. And they did not sound good what so ever. They did not have a balanced sound and had some serious phasing issues. I have heard the Dali's and the McIntosh ones. They both sounded good to very good, but to my ears they do not sound natural. I believe it is the distortion caused by they coupling of the drivers. But, there is always 400Hz and 2.5KHz resonances that I seriously find rather annoying. I don't find them to be smooth or natural at all. And the ones that use Ribbon or Planar technology are even worse. When I listen to a system I want to be fooled. I want the system to vanish and there just to be music. No box, no drivers, no crossover, no amplifiers, no pre-amp, no source unit, just music. I don't hear this with a Line Source system, I hear lots of dynamics. I hear lots of volume. In the McIntosh speakers I heard boat loads of clarity. But they still don't sound natural enough for my ears. There is something that is just not there. And it is the same thing that is missing when I listen to electro-static systems. There is something missing. If I figure it out exactly what it is I'll let you know...

thylantyr

12-25-2006, 06:38 PM

The problem I have with your line array bashing is because you are
bashing a concept, not a specific design. It's like bashing a TMW design
vs. bashing a specific TMW design. You might as well preach that chicken
soup takes bad.

You are complaining that you heard a DIY line array that was load and
didn't sound good. Well then, who's fault is that? Do you blame the concept
of the line array or is it better to say the specific DIY line array you heard
wasn't a good design ? lol

Re: McIntosh line arrays. The only one that has potential to sound good is
the newest XRT2k;
http://www.mcintoshlabs.com/mcprod/shopdisplayproducts.asp?hid=1&id=20&cat=Loudspeaker+Systems&prodid=1114&product=XRT2K

But I can pick apart that design and show some flaws. lol

Re: Dali Megaline
Of all the commercial line arrays, this is the lesser of the evils. It has potential
to sound good, but it's not he best you can make DIY style.

thylantyr

12-25-2006, 06:54 PM

Im trying to get the most objective perspective, and im glad im getting another opinion on these speakers.

I can probably make a list of individuals familar with a good line array
design so you can get more testimony.

From what I've seen, here are some issues that people complain about
in regards to line arrays.

1. Cost. People always complain that they don't have money to execute
a line array design. Line arrays have a dollar disadvantage because
you need alot of drivers.

2. Crossover Design. Just like any other loudspeaker design, lacking a good
crossover design is not sweet. A line array with an digital crossover like a
DCX allows you can extract maximum performance of any loudspeaker, but
many people in the DIY world don't go fully active due to the complexity of
the setup and additional cost.

3. Big Sound Stage. They don't like the big sound stage because they are
use to listening to small speakers. It's hard for some people to make the adjustment. For me, I had no issues. I like the wall of sound. This isn't the line
array's fault, the person who designed the array created the large image size.
If you implement power tapering you can make the image normal size. Power
tapering can cause an increase in distortion but it's probably a moot issue unless
you are an power user and want to extract maximum performance all around.

4. Theorists.
These are the folks who worry too much about the science behind a project
that they can't accept the design even if there is no audible gremlins. I have
seen a few of these types in cyber.

thylantyr

12-25-2006, 08:43 PM

Line array pics that I've collected over time. Some are commerical, some are DIY,
some are good designs, others not as good. Many hybrid designs.

http://home.pacbell.net/lordpk/speaker/

1. I think the first think you need to figure out is if you want OB, sealed, or a ported design.
2. Determine SPL goals.
3. An array of smaller ribbons or planars would be my first choice if you want higher SPL. $25 - $100 ea. is a good price range for them.
4. Remainder of the budget will go towards the midwoofers. < $30 ea. will get you many candidates.
5. Make a full line array of tweeters and midwoofers, near floor to near ceiling height.
6. DCX2496 digital crossover.
7. Four channels of amplification minimum.
8. Wire the array with an impedance switch for selection of low and high impedance.

Yeah I dont really understand why you dont like them...theres several designs and bashing a concept isnt really credible.

I dont understand how there would be any distortion problems with using multiple drivers as long as the acoustic centers are within 1/2 wavelength for nearfield listening or 1 wavelength for farfield. The drivers will have less distortion by several orders of magnitude compared to a single driver...

Its certainly a different sound due to the absence of floor/ceiling reflections and much less distortion. Im not familiar with B&W loudspeakers, but maybe they incur a higher level of even order distortion that you find satisfying, on the same level that some enjoy the distortion brought about by tube amplifiers. Further information to reinforce this idea is the fact that you hate ESLs, due to their push-pull design they lack even-order distortion.

It also could be psychoacoustics, who knows?

thadman

12-25-2006, 10:07 PM

Could you be more specific on what you found unnatural about them?

400hz and 2500hz resonances? Are those simply areas where you're sensitive to distortion? What are you trying to say...?

Loads of Volume and Dynamics...hmm. You dont *have* to crank them up, volume shouldnt be an indicator of sound quality as you can control that variable quite easily. I dont see how having loads of headroom and dynamics could be a bad thing...I really dont. Maybe im misinterpreting what you're trying to convey?

ngsm13

12-25-2006, 10:10 PM

I've listened to a lot of B&W's at a local high-end audio dealer, and I've found them to be very transparent.

nG

ballstothewall

12-25-2006, 10:13 PM

To me this argument seems very similar to the Chevy vs. Ford argument. Same **** different pile...

thylantyr

12-25-2006, 10:20 PM

To me this argument seems very similar to the Chevy vs. Ford argument. Same **** different pile...

There is no argument. Someone here may be interested in building one
so all we do is provide data to help the design turn out best. Of course you
will get some folks to say 'I don't like them'. It's no big deal.

I encourage auditions in conjunction with data gathering. You should listen
to speakers before you buy or at at least audition types of speakers to
get a mental picture on what each type does. It's much harder to audition
arrays because they are harder to find at the local store.

ballstothewall

12-25-2006, 10:31 PM

Then there is also a problem of living out in the sticks where there isn't **** to audition...

thylantyr

12-25-2006, 10:40 PM

Then there is also a problem of living out in the sticks where there isn't **** to audition...

Could be worse.. no internet........... no p0rn :laugh:

thadman

12-25-2006, 11:22 PM

I wonder how those B&Ws measures...:uhoh:

Im sure they sound phenomenal (which is one of the many reasons why they can demand such a high price tag), but if they incur a higher level (higher compared to minute distortion levels produced by esls and line arrays...) of distortion it may explain why you dont enjoy ESLs or line arrays. Distortion isnt necessarily a bad thing and is quite preferable in some situations. You may be used to hearing a certain level of distortion in speakers...and if its missing you might classify the new sound as *unnatural* or missing something. ...just a theory:cool:

This is one of the many reasons I want objective impressions of loudspeakers and not subjective ones. Words and phrases convey different opinions, emotions, and ideas to different people... As humans we are also subject to psychoacoustics and may hear what...we want to hear. Objective isnt like that, its a standard that can only be interpreted one way and may be able to explain the discrepancies we find in subjective comparisons

ngsm13

12-26-2006, 12:04 AM

I wonder how those B&Ws measures...:uhoh:

Im sure they sound phenomenal (which is one of the many reasons why they can demand such a high price tag), but if they incur a higher level (higher compared to minute distortion levels produced by esls and line arrays...) of distortion it may explain why you dont enjoy ESLs or line arrays. Distortion isnt necessarily a bad thing and is quite preferable in some situations. You may be used to hearing a certain level of distortion in speakers...and if its missing you might classify the new sound as *unnatural* or missing something. ...just a theory:cool:

This is one of the many reasons I want objective impressions of loudspeakers and not subjective ones. Words and phrases convey different opinions, emotions, and ideas to different people... As humans we are also subject to psychoacoustics and may hear what...we want to hear. Objective isnt like that, its a standard that can only be interpreted one way and may be able to explain the discrepancies we find in subjective comparisons

Sound inherently IS subjective. :fyi:

nG

ballstothewall

12-26-2006, 01:22 AM

I want objective impressions of loudspeakers and not subjective ones.

You do realize thats like seeking the holy grail, don't you...

Just go listen to the **** things, form your own fricking opinion, and be done with it.

thylantyr

12-26-2006, 02:13 AM

Here is more data for you to digest. Magnetar on diyaudio is a big horn speaker
freakazoid. Normal speakers never satisfied him. Recently, he got curious about
line arrays and built a budget array using a $3 midrange and Dayton Neo
$4 tweeter;

Magnetar said;
Well let me build some baffles and see what really happens before you make me change my mind!

What inspired me to do this line array thing was hearing a 96 driver line using 30 cent one by three inch TV speakers at fellows house a couple of weeks ago.

The tiny drivers were in 3' wide sealed baffles with no tweeters and some little 6.5" isobaric bass drivers built into sub enclosures(biamped) in the back of the baffles for below 120 cycles. Other than the size (bigger then my horn systems at over 8 feet tall and 3 feet wide and aaround a fooot and a half deep!) and lack of high frequency extension I was pretty impressed with the sound. Mostly In the way the lines drove the room and the huge sweet spot. The upper bass and mids were very coherent and his line arrays projected a nice meaty, 3D image that was quite enveloping and full size. They also would play at serious levels with little strain like a good horn.

He used no eq at with this and up to 6k or so, I feel this 96 driver system is superior to my Acoustat Spectra 3 electrostats. His line was also easier to drive, no beaming, and walked all over the Acoustats in dynamics and pure FUN - The Acoustat is a pretty good sounding panel speaker with it's segmented panels.

So what I'm hoping to do is get these $ 3.00 drivers to sound as good as his 30 cent drivers with some response above 10K and a smaller footprint.

*****

Project done;

They are nearing completion and sound wonderful.

I ended up using 30 tweeters, 12 midrange and 6 ten inch pro bass drivers per channel in a triamped open baffle. The bass is measuring in at a whopping 108 DB/W/M and is very tight and tuneful...

What is amazing is it's the first time my horn loaded sub bass actually has seen it's match in the midbass.

Imagine what happens when you build a quality array with better drivers. /hehe
http://www.diyaudio.com/forums/showthread.php?threadid=89188&perpage=10&pagenumber=1

Now you know why I have 288 NSB's in storage, 49 cent midwoofers. This is good stuff in an array,
you can beat down very high end store speakers for minimal costs and laugh all the way to the bank.

Those fosters may be a candidate for lacquer cone treatment to improve SQ and lower cone mass, harr................

joetama

12-26-2006, 02:19 AM

You do realize thats like seeking the holy grail, don't you...

Just go listen to the **** things, form your own fricking opinion, and be done with it.

Agreed.... No more Propaganda, no more hype.... Get what you like.... And be done with it..... I don't care what you get. Just don't **** in my bucket and tell me it's raining when I give you my opinion when you asked for it....

desertheat

12-28-2006, 03:36 PM

Good info :) Hey that McIntosh new line uses aura 2" titanium drivers... haha nice!
I can get the 3" paper drivers from aura for pretty cheap. I have been dreaming up an array useing approx 40 drivers per side... Man sounds fun haha. Still trying to decide HF for the array and what drivers... DIY is why I am into car audio, makes it fun and more enjoyable and sometimes your results end up amazing !

Hahaha that ***** man... 89db with 110 drivers..? *LOL* OMG.. I would have guessed 106db+++!

Very cool. I dig the responce of those aura 3" drivers.. Mabey do just a super tweet up way high around 10-12K?? Somthing like the crossoverpoint on a hammerdynamics 2way? Just a thougt I am having :) Heck I may even be able to skip the tweet and go for a full range setup with those.. Have heard a few full range setups that really changed my perspective on audio and what I like and do not like...

Also looking at these...
http://www.madisound.com/pdf/aurasound/ns4-255-4d.pdf

Not near the nice responce of the 3" but the fs is around 75hz lower. Could help bring the crossover point allot higher... Still learning allot but I have some ideas of what I want out of my monoliths...

http://www.madisound.com/pdf/aurasound/NS3-193-8A.pdf

thylantyr

12-29-2006, 03:27 AM

What is your two tower line array budget ?
What is the important variables? high quality high frequency SQ? SPL? bass > treble performance? etc.

Also looking at these...
http://www.madisound.com/pdf/aurasound/ns4-255-4d.pdf

Mad pricing = $25 each.

Lets say 16 4" drivers per tower. Mad pricing = $400 per tower.

These are $19.50
http://www.madisound.com/pdf/aurasound/NS3-193-8A.pdf[/QUOTE]

Lets say 20 3" drivers per tower. Mad pricing = $390 per tower.

Using Madisound pricing, two midwoofer towers can cost $340 - $800
with no tweeter. Sound quality won't be the best without a tweeter array
or a very high performance single tweeter.

If you want high fidelity, then look at a tweeter array, the Dayton PT2 tweeter, eight or more per tower
can do a great job, even better job wired for lower impedance. That cost about $400 for two towers
for 16 tweeters total. 20 - 24 tweeters is ideal for a 8' tall home. Find whatever midrange that will get
the bass response you seek. Let the PT2 operate in the 1.7khz - $3khz range and use the appropriate
mid that has less cone break up gremlins at the target crossover frequency. Model a ported box to extract
more bass to see if that is an option.

I can't think of any single tweeter in the lower price range that will compete
with a midwoofer array. You can use compression drivers and horns and some
other exotic tweeters, but how much do they cost vs. the PT2 array?

If you did make a PT2 array, then there is no reason to limit your midwoofer
to 3" or 4", you can go bigger in size. Many fancy drivers > 6" may not work
well due to cone breakup issues in the 2khz - 3khz region. If you use a LR8
crossover, you can cheat the PT2 to work in the < 2khz range and LR8 will filter
out the nasty midwoofer gremlins that may manifest with drivers > 6" in size.
It depends on the midwoofer you choose.

Line arrays are actually easy to create if you have money. Go active and pick
the drivers to make a tweeter line and midwoofer line and no hybrid idea
so you can get the best performance. Get four quality amp channels that drive low impedance,
viola'.. yer done.

desertheat

12-29-2006, 04:37 AM

This is pretty much my vision.... The tweet I am still in the air on... possibly looking at a raven r1... Anyways bi-amp was already planed for. My idea is to keep the mids playing up to around 10-12Khz at least so the tweet would be very top end only... just my idea anyways... And yeah, I know these things get pricey but your talking to a guy that spent $23K in modifications to a $16K car hahaha! You only live once right! And on aura prices... yeah.. very very cheap *LOL*! Think I am the aura ***** on here.

http://www.garage1217.com/AUDIODESIGNS/linearray.jpg

Feel free to tear into my thought process on this design. I am still learning heavily when it comes to arrays....

thylantyr

12-29-2006, 02:49 PM

The line array guideline seen here;
http://www.audiodiycentral.com/resource/pdf/nflawp.pdf

3" speakers with 3" center to center spacing would yield a crossover point of;

13560 / 3 = 4520hz, optimum is to divide that by two = 2260hz

Combing probably begins at 2x 4520 = 9040hz

If you were ****, 2.2khz crossover.

Gremlins probably arn't audible at 4.5khz crossover.
You may start to hear something as you raise that crossover because
those are full range drivers. If you have a variable electronic crossover
like DCX2496 you can do a test hear the audible effects of different crossover
frequencies. Experiment by sweeping the crossover frequency from a low setting,
lets say low pass 2khz and sweep all the way up to 20khz and listen for any sounds
that you think might be compromising the design and note the crossover frequency.

Lets say the sound is cool at 10khz crossover, but starts to sound worse
if you raise it higher, then you need the tweeter. But, what if it sounds good
to you with the high pass setting at 20khz or no high pass ? Then no need for a tweeter.
You have to make a 1 tower prototype of the midwoofer array to audition it and find
out where gremlins manifest if any. Then you can proceed to the next step.

Lets say you prefer a lower low pass setting, lets say 3khz - 5khz, then you
will need a tweeter that will mate well with the SPL potential of the midarray
or you will have to reduce midarray SPL to match the single tweeter as it is
the weakest link.

If you want best SQ, you will need a tweeter array. An array of ribbons or planars
or a big array of those $4 dome tweeters. 40 of the $4 dome tweeters per tower
would be a wiring hell, but you can do some big damage with a big tweeter array
like that. If you make the array more complex, then you should consider going fully
active. If you want to keep is simple with only full range drivers and a single tweeter,
then use passive if you want. But if you have an array of tweeters and mids, fully
active makes it easier to tweak.